Skip the auto shop - Our mechanics make house calls

Q: Engine puffs blue smoke; thumping noise at highway speeds

asked by on

In the mornings when I start my SUV, for a few seconds the engine puffs blue smoke. When I’m driving on the highway at 60 mph, it begins to make a very obnoxious thumping sound that can also be felt by the vibrations. It feels like there is something stuck to the tire, but when I examine them, I don’t find anything. With more speed, the louder it becomes. I have looked at the transmission, driveline, shafts - all seem fine. Another problem is that when I am braking, the steering wheel shakes and there is a loud noise under the brake pedal. I have already changed the brake pads and the rotors, machined them, etc. No repairs have worked! I would greatly appreciate your advice on what will fix my car. Thanks.

A: Hi there, thanks for asking about your 2004...

Hi there, thanks for asking about your 2004 Infiniti FX45. The blue smoke you notice on initial start-up is likely caused by worn exhaust valve stem seals. They allow a tiny amount of oil to get into the combustion chamber while the car sits overnight. This will slowly get worse with additional miles until the valve stem seals are replaced. Have the front tires and wheels checked for balance, "roundness", or any separation of the tread of the tire at a reputable tire dealer. There is likely something amiss that’s showing up at highway speed and under braking. If you want to have this checked by a certified mechanic, a technician from YourMechanic can come to your home or office to inspect the smoke coming from your car’s exhaust.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Brakes wear out fast. 1996 GMC C2500

Hello there. It does sound like your 1996 GMC C2500 has gone through an excessive amount of brake components. There are a few things that can cause premature brake component failure. Sticking calipers and wheel cylinders are the most common....

Q: Smoke entering car from the engine compartment.

The smoke coming from behind the steering wheel is a sign that something is shorting or making poor contact and you may be in danger of a fire starting from continued use or possible air bag going off with out...

Q: Should I be able to spin front wheel by hand while other wheel is on the ground

Hey there, thanks for writing in about your 2002 Jeep Grand Cherokee. Make sure that you are not in four-wheel drive mode. Sometimes when the hubs lock, they make a clunking noise and the whining noise could be a gear...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.